The optimal use of prophylactic antibiotic therapy to prevent infection after sinus lift and augmentation surgery is unknown. This is a comparative open label interventional trial comparing a standard 7-day course of postoperative treatment with amoxicillin-clavulanate with short antibiotic treatment for up to 24 hours postoperatively. The primary study outcome is the postoperative surgical site infection in the standard versus the short treatment arms. Secondary outcomes are drug-related adverse events and Clostridium difficile infection.